Dampener mechanism



March 28, 1944. GARDNER 2,345,337

DAMPENER MECHANISM Filed March 19, 1942 FIG. I

INVENTOR ALEXANDER GADDNEQ. BY v24 A OR-NEY Patented Mar. 28, 1944 UNITED STATES PATENT OFFICE DAMPENER MECHANISM Alexander H. Gardner, Passaic, N. J., assignor to Collins & Aikman Corporation, Philadelphia, Pa., a corporation of Delaware Application March 19, 1942, Serial No. 435,309

7 Claims.

This invention relates to improvements in dampening mechanism and rolls for lithographic presses and similar machines. A typical and conventional dampener assembly of this type is found on the so-called Harris offset lithograph machine manufactured by Harris, Seybold-Potter Company of Cleveland, Ohio, and includes a pan or fountain for accidulated water or other treated liquid, a fountain roller, a ductor roller, and one or more dampener rollers which cooperate to convey the water or other liquid to the lithographing plate in a known manner. For convenience I shall hereinafter refer to the liquid in the fountain as water.

More particularly my improvements are directed to the covering for the ductor roll and dampening rollers, whose functions are to aid in conveying the water to the dampening rollers and in applying the water to the press plate by intimate contact of the dampening roller or rollers and the press plate. The water moves by external contact with the several rollers from the fountain to the lithographic press plate.

It has been a prior practice to use a molleton covering for the ductor and dampener rolls. This covering is or resembles a thick felt fabric. It is difficult to remove the ink which accumulates on and in molleton or felt during operation and it is somewhat unsatisfactory in use. According to my improvements I have found that by using a heavy dense and cut type warp pile fabric that the water can be conveniently controlled and that the dampening of lithographic plate can be more satisfactorily carried out.

My improved cover improves the general operation of the dampener assembly, reduces the number of times that the covers must be changed, cleans readily, results in a minimum of dampener marks on the work and reduces the necessary amount of cushioning required for the cover When it is in position on the rolls. The control of water afforded by my cover has the eifect of minimizing the amount of water used and hence reduces the danger of an excess which may cause marks in the finished work. The rollers when covered by my novel cover as by sewing are smooth on the outside because the sewing thread is buried in the pile face. This cover insures that the plate is properly dampened at each necessary point without producing lint or a shedding of the pile. The dampening is done by the ends of the fibers rather than by their sides or lengths.

An object of my invention is to provide an improved dampener assembly for the press plates of lithographic and similar presses.

A further object is to provide a cut pile fabric having a cellulosic pile portion, such as cotton, ramie, linen or rayon, or blends of the same, for use as a cover for dampener and like rolls.

Another object is to provide a heavy dense face pile fabric for use as a cover for dampener rolls, which fabric cover makes the water more readily available for use.

Another object is to produce a dampener roller in which the cover portion will not tend to creep or bunch on the roll.

Another object is to provide a dampener roll in which the sewing thread for the cover is buried in the surface and does not contact the press plate.

Another object is to provide a cover for lithographic dampener rolls which is so compressible that the use of rubber rollers in the form of cores for the cover or for use alone may be dispensed with.

Another object is to improve dampener assem blies for lithographic presses of the type in which the dampener roll has a periphery speed substantially the same as that of the plate which it is to dampen.

These and other objects of invention will be manifest from a consideration of the following description, claims and drawing, in which,

Figure I is a diagrammatic assembly view of a conventional dampener assembly with my novel cover incorporated therein.

Figure II is a diagrammatic view looking weftwise of my improved fabric.

Figure III is a modification including a cushion backing integral with the fabric.

Figure IV is a modification including an adhesive back which is reenforced with a plain flat fabric or the like.

Referring to Figure I, there is illustrated a fountain l0, into which fountain roller II, which may be covered with cheese cloth, linen, muslin, or other moisture absorbing material, is intermittently immersed as by levers l2 and is then moved into contact with continuously revolving roller i3. Roller l3, which may be of metal or rubber, conveys the water to my covered ductor roller M, which in turn dampens the roll l5, which is similar to roll I 3. My covered dampener rolls i6 and I! pick up the water or other liquid from the roller [5 and dampen the press plate Hi. It will be noted that the dampening rollers move at the same or substantially the same speed as the press plate roller 18 and that there is no objectionable brushing action.

Figure II shows a fabric covering per se in a simple embodiment. The fabric is consistsof a set of tight warp threads 20, a set of oppositely woven slack warp threads 2 I, wefts 22, 23 and pile Vs 24, which are looped about every weft in every dent space during the weaving process. It is to be understood that variations in the weave may be made but that the fabric is designed to have a compact pile face of low resilience so as not to throw water. By low resilience is meant a limited springing back action when the pile face is distorted by rubbing. This term is characterized and illustrated by the action of cotton pile as opposed to the stiffer hair fibers such as mohair. The compressibility of the pile face of my cover in use is definitely greater than molleton cloth or felt, however, and insures intimate contact with the press plate is at all points of desired contact. This compressibility permits the cover to beusedonhardcoresaswellastobeusedasa substitute for rubber dampener rollers.

For the above reasons the brush-like hair fibers such as mohair are to be avoided in the pile and cellulosic fibers such as cotton, ramie, linen and rayon are to be used. The tight warps cause the weft to lie in two different planes and permit the pile face of the fabric to be made more dense. In order to insure permanency of this structure, I prefer two or more tight warps for each slack warp and I have found that the ratio of three tight warps to one slack warp to be very satisfactory in use.

If desired, the fabric may be impregnated and/or coated on the back with rubber or other adhesive in a known manner. This will aid in securing the pile in position, and in the case of a coating as at 25 it may vary in thickness and may serve as a cushion as well as prevent raveling of the cloth when out for attachment to the roll. If the back of the fabric is merely impregnated or is a sponge rubber back, the fabric may retain its porosity for use with or without one or more inner absorbent felts. This is of importance when the rate of water feed has been set too high, as the excess can be taken up. The rubber coating may be reenforced by a fabric 26 embedded in or attached to the back of a coating. The coating may be resilient, such as a soft or sponge rubber. This expedient avoids the use of auxiliary felt rolls as are used under prior covers. Even without the coating a minimum amount or no cushioning is required, as the depth of the fabric and compressibility of the pile in themselves will function as a cushioning means.

The specification for a fabric covering material especially suitable for the practice of my inven-- tion and within its scope is as follows. The fabric is woven 60 inches wide with 48 weft threads of 2/8s KP natural cotton weft threads to the inch. The slack and tight warps as well as the pile threads are 2/16's KP natural cotton yarns. In the 60 inch width there are 2,780 slack warp threads, 8,340 tight warp threads, or three tight warp threads which lie between single slack warp threads. The fabric thickness is .285 inch. The cloth is a warp pile fabric and may be wovendoubio and cut apart. I prefer that the fabric thickness be .15 inch or more and that it should not exceed .40 inch. It is essential that the pile be a cut pile so that the ends of the fibres will act substantially individually and so that the fibers will not break or pass from the fabric in the form of lint.

As was said in reference to the weave, variations in the above specification may of course be made, with the exception that the face of the fabric should be dense and the pile fibers must be of low sldewise resiliency to avoid throwing of water.

With the above in mind, it will be seen that water to which a small amount of chromic or other acid, as is customary, has been added can be uniformly transferred from the fountain to the press plate, that a less amount of water will be used, and hence a reduction in the danger of poor work resulting from an excess of water will be effected. It will further be seen that the pile fabric will present a more uniform face and will more evenly distribute the water without danger of throwing drops of water on the press plate, and that it will minimize dampening marks and reduce spoilage. The only wear on the fabric is on the ends of the fibers, and hence the resistance to wear will be increased. The fabric is easy to clean. The structure and nature of the fibers result in the fabric having a faculty for absorbing and holding water and the pile structure reduces or eliminates the need for fiannel or other cushions under the cover cloth.

The denseness of the fabric and its fibers insures a minimum of stretching, and hence there is no creeping on the roll. This is of particular importance in connection with high speed presses. In addition, there is no tearing of the fibers as will result from the fiat contact of feltlike cloths, as only the ends of the individual fibers, as opposed to entire threads or nap surfaces, are in contact with the press plate.

From the above it will be seen that I- have substantially improved the operation of lithographing and like machines by my improvement to the dampener assembly unit contained therein. I do not wish to be limited by the preferred illustrated embodiments, but only by the scope of the following claims.

Having described my invention, I claim:

1. In a dampener assembly of the vtype in which water is conveyed by external contact of rollers, a dampener roller which comprises a core portion and an outer cover portion, said outer cover portion being a woven cut pile fabric having a dense water absorbent pile face of cellulose fibers and low side-wise resiliency.

2. In a dampener assembly of the type in which water is conveyed by external contact of rollers, a dampener roller which comprises a core portion and an outer cover portion, said outer cover portion being a woven cut pile fabric having a dense water absorbent pile face of low lateral resiliency and containing cotton.

3. In a dampener assembly as set forth in claim 1, further characterized in that the pile fabric thickness is greater than .15 inch.

4. In a dampener assembly as set forth in claim 1, further characterized in that the pile fabric comprises tight backing'warps and slack backing warps.

5. A woven pile fabric for covering dampener rolls of lithograph and like presses which comprises a set of weft threads, a set of slack warp threads, a set of oppositely woven tight warp threads and pile tufts wholly or partially of cellulose fibers, said pile tufts forming a dense face of low side-wise resiliency, the fabric being greater than .15 inch in thickness, whereby substantial compressibility will result. 

